This invention relates to a method of shifting strands to a front waste take-up portion at the front end of a spindle when the spindle is fully wound in the production of glass fiber which method is suitable for use in carrying into practice a method of drawing a multiplicity of filaments from a glass melting furnace, dividing them into a plurality of strands and winding such strands on a single spindle to form a plurality of square-ended packages thereon.
Nowadays, the nozzle formed at the bottom of a bushing for drawing molten glass as filaments in producing glass fiber has as much as several thousand holes. The filaments drawn from such nozzle of a multiplicity of holes are divided and formed into a plurality of strands depending on the use to which the glass fiber is put. The strands are wound into a plurality of packages. In forming a plurality of packages, to simplify the equipment, a plurality of strands are wound on a single spindle of a take-up device to form a plurality of packages thereon. Typical packages formed in this way include double-tapered packages and square-ended packages.
In forming a plurality of packages on a single spindle, the spindle that has been fully wound should be replaced by a new spindle. In effecting spindle replacements, the following steps are generally followed. First, all the strands are temporarily shifted to the front waste take-up portion at the front end of the fully wound spindle and then shifted to and wound on a strand transfer drum moved close to the front waste take-up portion. During this process, the fully wound spindle is replaced by a new spindle, and the strands are shifted again to the front waste take-up portion of the new spindle following completion of switching of the spindles. Thereafter the strands are shifted back to their predetermined positions on the spindle. In this fashion, the fully wound spindle can be replaced by the new spindle without interrupting the movement of the strands or the operation of drawing glass fiber.
When the plurality of packages formed on a single spindle are double-tapered packages, it is possible to shift the strands to the front waste take-up portion of the fully wound spindle merely by moving slowly the strands to be wound on the packages to the front end of the spindle by means of a shift guide. More specifically, since a double-tapered package has a tapered portion on either end of a cylindrical center portion, the strands intended for other packages can be shifted smoothly as they pass the tapered portion, cylindrical center portion and tapered portion in that order as the shift guide moves in the aforesaid direction, so that the strands can be shifted to the front end of the fully wound spindle without any trouble. However, when the packages formed on a single spindle are square-ended packages, difficulties have hitherto been encountered in shifting the strands to the front waste take-up portion of a fully wound spindle, due to the fact that a deep groove is defined between the adjacent packages on the spindle. It is impossible to shift the strands across each package merely by moving them transversely over each package because the strands drop into the groove. To cope with this situation, it has hitherto been necessary to temporarily shut off the take-up device and stop winding of the strands and, following replacing of the fully wound spindle by a new one, to align the filaments continuously drawn from the glass melting furnace and manually wind them on the front waste take-up portion of the new spindle, simply because of inability to shift the strands to the front waste take-up portion at the front end of the fully wound spindle. Such operation is not only troublesome but also time consuming. Thus the method of the prior art of replacing the fully wound spindle by a new one has had the disadvantage of causing a marked reduction in the operation efficiency of glass fiber drawing machines.